-------------------------------------------------------------------------------
--
-- Copyright (C) 1999 FlightSafety International and Ted Dennison
--
-- This file is part of the OpenToken package.
--
-- The OpenToken package is free software; you can redistribute it and/or
-- modify it under the terms of the  GNU General Public License as published
-- by the Free Software Foundation; either version 2, or (at your option)
-- any later version. The OpenToken package is distributed in the hope that
-- it will be useful, but WITHOUT ANY WARRANTY; without even the implied
-- warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU General Public License for  more details.  You should have received
-- a copy of the GNU General Public License  distributed with the OpenToken
-- package;  see file GPL.txt.  If not, write to  the Free Software Foundation,
-- 59 Temple Place - Suite 330,  Boston, MA 02111-1307, USA.
--
-- As a special exception,  if other files  instantiate  generics from this
-- unit, or you link this unit with other files to produce an executable,
-- this unit does not by itself cause the resulting executable to be
-- covered by the GNU General Public License.  This exception does not
-- however invalidate any other reasons why the executable file might be
-- covered by the GNU Public License.
--
-- Maintainer: Ted Dennison (dennison@telepath.com)
--
-- This software was originally developed by the following company, and was
-- released as open-source software as a service to the community:
--
--           FlightSafety International Simulation Systems Division
--                    Broken Arrow, OK  USA  918-259-4000
--
-- Update History:
-- $Log: opentoken-recognizer-integer.ads,v $
-- Revision 1.2  1999/12/27 19:56:02  Ted
-- fix file contents to work w/ new hierarchy
--
-- Revision 1.1  1999/12/27 17:11:36  Ted
-- renamed everything to new hierarchy
--
-- Revision 1.4  1999/10/08 23:15:42  Ted
-- Add Get parameter to allow signed literals
--
-- Revision 1.3  1999/09/17 02:02:56  Ted
-- Fix comment typo
--
-- Revision 1.2  1999/08/17 03:04:15  Ted
-- Add leading zero function (CKWG)
--
-------------------------------------------------------------------------------

with Opentoken.Recognizer.Extended_Digits;

-------------------------------------------------------------------------------
-- This package implements a token recognizer for an integer. An integer is
-- defined as a string starting with a series of digits, optionally followed
-- by an exponent specification.
-- An exponent specification is a letter 'e' (or 'E') followed by an optional
-- plus sign and decimal digits.
-- Each of the sequences of digits may be interspersed with one or more single
-- underscores (but must not end with an underscore), if not explicitly dis-
-- allowed.
-- When this recognizer and the one for Java style based integers are used
-- together in the same syntax, note that the integer recognizer must be
-- created with leading zero disallowed or a string like 07 is ambiguous.
-- (However 0 is always a simple integer.)
-------------------------------------------------------------------------------
package Opentoken.Recognizer.Integer is

  type Instance is new Opentoken.Recognizer.Instance with private;

  ----------------------------------------------------------------------------
  -- This procedure will be called to create an Integer token.
  --
  -- One would probably want to disallow signs in languages that use '-' or
  -- '+' as an operator between integers. If your syntax does not have such a
  -- concept, you will probably want to allow them.
  ----------------------------------------------------------------------------
  function Get (Allow_Underscores  : Boolean := True;
                Allow_Exponent     : Boolean := True;
                Allow_Leading_Zero : Boolean := True;
                Allow_Signs        : Boolean := True
               ) return Instance;

private

  type State_ID is (First_Char, First_Numeral, Numeral, Exponent_Sign, Exponent, Done);

  type Instance is new Opentoken.Recognizer.Instance with record

     Allow_Exponent     : Boolean;
     Allow_Leading_Zero : Boolean;
     Allow_Signs        : Boolean;

     -- The finite state machine state
     Decimal_Recognizer : Extended_Digits.Instance;  -- Numeral, Exponent
     Last_Verdict       : Analysis_Verdict := Failed;
     Check_Zero         : Boolean          := True;
     State              : State_ID         := First_Char;

  end record;

  ----------------------------------------------------------------------------
  -- This procedure will be called when analysis on a new candidate string
  -- is started. The Token needs to clear its state (if any).
  ----------------------------------------------------------------------------
  procedure Clear (The_Token: in out Instance);

  ----------------------------------------------------------------------------
  -- This procedure will be called to perform further analysis on a token
  -- based on the given next character.
  ----------------------------------------------------------------------------
  procedure Analyze (The_Token: in out Instance;
                     Next_Char: in     Character;
                     Verdict  :    out Analysis_Verdict);

end Opentoken.Recognizer.Integer;
